Manipulating electrostatic field to control the distribution of bioactive proteins or polymeric microparticles on planar surfaces for guiding cell migration.

We report a general strategy to generate linear and circular gradients of active proteins or polymeric microparticles on planar surfaces by controlling the distribution of electrostatic field during electrohydrodynamic jet printing or electrospray process. Taking fibronectin as an example, we generated a circular gradient of fibronectin and investigated its effect on accelerating the migration of fibroblasts to suit for use in wound closure. In another demonstration, we created linear gradients of laminin in unidirectional and bidirectional patterns, respectively. We showed that such gradations significantly promoted the migration of human neuroblastoma cells with the increase of laminin content. When we changed fibronectin/laminin to electrosprayed poly(lactic-co-glycolic acid) (PLGA) microparticles, we found similar results in terms of guiding cell migration, except that the guidance cues varied from biological signal to topographic structure. Taken together, this method for generating linear/circular gradients of fibronectin/laminin and PLGA microparticles can be readily extended to different types of bioactive proteins and polymeric microparticles to suit wound closure, nerve repair, and related applications involving cell migration.